Weight Of Digestive Organs Research Articles

Effect of milk deprivation during the lactation period on performance and digestive enzyme activities of the piglets following weaning

Post-weaning performance of piglets from systems where lactation is disrupted (e.g. from multisuckling systems) is superior to conventionally reared piglets. The objective of this study was to establish whether restricted growth prior to weaning caused by disruption of suckling was an important factor in post-weaning performance and also whether there were related changes in gastro-intestinal development. Ten litters of eight piglets were used in a split-plot design. Half of each litter (limited suckling, LS) had suckling disrupted by separation from their dam for 7 h/day from day 14 to 28 after farrowing. The remainder of each litter was allowed to suck normally (normal suckling, NS). The same amount of creep feed was offered to LS piglets as consumed by NS littermates on the previous day. There were no differences in weight between LS and NS piglets at 14 days of age, but restricting access to the sow reduced weaning weight at 28 days of age (7.96 v. 9.00 kg; LS v. NS; P < 0.01; s.e.d. 0.23). Feed intakes were greater for LS than NS piglets over the first 28 days post weaning, particularly in the 1st week after weaning when feed efficiency was also improved (0.91 v. 0.62 kg gain per kg feed; P < 0.01; s.e.d. 0.08). As a result, LS piglets grew more rapidly in the first 28 days post weaning, particularly in the first 7 days after weaning. Subsequent performance to 8 weeks was similar for both groups. Digestive organ weights were not different at 2 and 9 days after weaning; nor were small intestine specific enzyme activities significantly different ( P>0.05). Pancreatic trypsin activity was, however, greater ( P < 0.01) for LS pigs on both days 2 and 9 post weaning. In conclusion the restriction of growth as a result of limited suckling itself is an important factor in determining post-weaning performance and may be related to development of pancreatic trypsin activity.

Effect of a commercial essential oil on growth performance, digestive enzyme activity and intestinal microflora population in broiler chickens

The present study was designed to evaluate whether a blend of essential oils (EO) extracted from herbs could affect growth performance, digestive enzymes and antimicrobial activity of the gut in growing broiler chickens. A total of one hundred and twenty, 3-day-old male broiler chickens were assigned to the basal diet (CON) and the basal diet supplemented with 10 mg antibiotics/kg diet (ANTI), 25 mg EO/kg diet (EO I) and 50 mg EO/kg diet (EO II) until 35 days of age. Throughout the entire feeding period (3–35 days), there were no differences in body weight, feed intake, total gain and feed:gain ratio among the birds fed the basal diet and the diet supplemented with antibiotics, either low (EO I) or high level of EO (EO II). Weights of digestive organs including the liver, pancreas, intestine and mucosal tissues were not affected by the dietary treatments. Total and specific activities of pancreatic trypsin significantly (P<0.05) increased in birds fed EO II diet compared with those fed CON and ANTI diets. It was also observed that the total activities of pancreatic α-amylase and intestinal maltase significantly (P<0.05) elevated in birds fed EO II diet compared with those fed CON diet. The colony forming units (CFU) of Escherichia coli in the digesta of ileo-cecum in the ANTI group showed a significantly lower number compared with that in the CON group. However, there was no difference in the CFU of E. coli between the ANTI and EO groups. The CFU of lactobacilli was unaffected by dietary supplementation of either EO or antibiotics. In summary, dietary addition of EO showed a decreased E. coli population in ileo-cecal digesta. Furthermore, a high dose of EO resulted in a significant increase in certain digestive enzyme activities of the pancreas and intestine in growing broiler chickens.

Digesta viscosity, nutrient digestibility and organ weights in African catfish (Clarias gariepinus) fed diets supplemented with different levels of a soluble non-starch polysaccharide

The objective of the present study was to investigate if dietary soluble non-starch polysaccharides (NSP) increase digesta viscosity, reduce nutrient digestibility and increase organ weights in African catfish. The fish (mean weight 80 g) were fed diets supplemented with the soluble NSP guar gum at three levels, 0 g kg1 (GG0), 40 g kg1 (GG4) and 80 g kg1 (GG8). Guar gum inclusion significantly increased digesta viscosity in the proximal (GG0: 1.7 centipoise or cP; GG4: 84.9 cP; GG8: 98.3 cP) and distal (GG0: 1.9 cP; GG4: 109.8 cP; GG8: 66.4 cP) intestine. Apparent digestibility coefficients (ADC) were significantly lower for the GG8 diet than the GG0 diet (dry matter: 52% versus 69%; protein: 77% versus 90%; ash: 41% versus 54%; energy: 60% versus 77%). The ADC of dry matter and energy were significantly lower for the GG4 diet than the GG0 diet. The relative growth rate of metabolic weight (14.5?15.4 g kg0.8 day1) and feed conversion ratio (0.8) did not differ between diets. Fish fed the GG8 diet had a significantly higher somatic stomach index than GG0 fish (0.71% versus 0.65% body weight). The intestinal somatic index tended to increase with increasing guar gum supplementation (GG0: 1.08%; GG4: 1.23%; GG8: 1.59%). In conclusion, high digesta viscosities in the guar gum fed fish may explain the observed reduced nutrient digestibilities and increases in digestive organ weights

Scavenging Pullets in Burkina Faso: Effect of Season, Location and Breed on Feed and Nutrient Intake

A study on scavenging local (n = 64) and crossbred (n = 64) pullets was undertaken in the dry and rainy seasons in two villages in Burkina Faso: Korea in the arid northern Sahelian region and Bounouna in the sub-humid south. After 4 weeks of scavenging, the birds were killed and the crop contents were subjected to physical and chemical analysis. Cereal grains, brans, green and dry forages, insects/worms and household leftovers were the main physical components. The proportion of cereal grains was higher in the rainy season, whereas the proportion of bran, peanut and sand/grit was higher in the dry season (p < 0.05). The proportion of kitchen waste and millet/milo grains was higher in local than in crossbred birds, whereas the opposite was the case for millet/milo bran (p < 0.05). Rice and local beer residues were not found in the crops of birds from Korea. Dry matter, ash, crude fibre and potassium contents were higher in the dry season (p < 0.05), while calculated metabolizable energy content was higher in the rainy season (p < 0.05). There were no location or breed effects on chemical composition parameters (p > 0.05), except that potassium content was higher in Korea. Mean live weight at slaughter was 806 +/- 22.0 g (local breed) and 881 +/- 22.0 g (crossbreds) (p < 0.05). Digestive organ weights, including contents, were higher for crossbred birds (p < 0.05). Gastrointestinal tract percentage was higher in the rainy season and in Bounouna (p < 0.05). The nutrient composition of the crop contents indicates the need for supplementation, particularly of protein, for higher levels of production.

Effect of In ovo Injection of Critical Amino Acids on Pre- and Post-hatch Growth, Immunocompetence and Development of Digestive Organs in Broiler Chickens

Two experiments were conducted to standardize in ovo injection of amino acids (AA) and to evaluate the effect of in ovo injection of limiting AA(s) on pre and post hatch growth performance, immune response and development of digestive organs. Combinations of essential and non-essential amino acids (Lys+Arg, Lys+Met+Cys, Thr+Gly+Ser, Ile+Leu+Val and Gly+Pro) were injected into 50 eggs in each treatment group at 14 d of embryonic age. Standardization of injection site, needle length and embryonic age revealed that when AA were injected in to the broad end of the egg with a 11 mm needle and at the narrow end with a 24 mm needle both at the 7 th and 14 th d of incubation there was poor hatchability. However, better hatchability was recorded when the AA were injected in the narrow end of the egg with a 11 mm needle and in the broad end with a 24 mm needle on the 14 th d of incubation. The chick to egg weight ratio was higher (p<0.018) when AA were injected on the 14 th d of incubation. When a combination of amino acids were injected a 63.6 or 63.2 g difference in body weight of bird at 21 d was recorded between uninjected control and Ile+Leu+Val or Gly+Pro group, respectively. Higher feed intake (p<0.047) was recorded in the AA injected groups and feed conversion ratio (FCR) was numerically better in Gly+Pro, Lys+Met+Cys AA injected groups than in the uninjected control. Significantly higher immune response to cell mediated (p<0.033) and humoral (p<0.002) immunity was observed in in ovo amino acid injected birds, especially in Lys+Met+Cys, Thr+Gly+Ser or Ile+leu+Val groups. The digestive organ weights at 21 d did not differ between specific AA injected groups and the uninjected control. In ovo injected amino acids may act as immunomodulators and their role in gastrointestinal development needs further research. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 4 : 524-531)

Influence of two plant extracts on broilers performance, digestibility, and digestive organ size

A 42-d trial was conducted to study the influence of 2 plant extracts on performance, digestibility, and digestive organ weights in broilers. The feeding program consisted of a starter diet until 21 d and a finisher diet until 42 d. There were 4 treatment groups: control; 10 ppm avilamycin (AB); 200 ppm essential oil extract (EOE) from oregano, cinnamon, and pepper; and 5,000 ppm Labiatae extract (LE) from sage, thyme, and rosemary. No differences in feed intake or feed conversion were observed. From 14 to 21 d of age, broilers fed the LE diet grew faster than the broilers fed the control or EOE feeds (68.8 vs. 63.9 and 61.6 g/d, respectively). Antibiotic and plant extract supplementation improved apparent whole-tract and ileal digestibility of the nutrients. For starter feed, LE supplementation improved apparent fecal digestibility of DM (P < 0.01), and all additives increased ether extract digestibility (P < 0.001). However, no effect was detected for CP digestibility (P > 0.1). At the ileal level, the AB, EOE, and LE supplementation of the starter feed increased DM and starch (P < 0.01) digestibility but not CP digestibility (P > 0.1). All additives improved apparent fecal digestibility of DM and CP of the finisher diet. No differences were observed for proventriculus, gizzard, liver, pancreas, or large or small intestine weight. In the present study, both plant extracts improved the digestibility of the feeds for broilers. The effect of different additives on digestibility improved the performance slightly, but this effect was not statistically significant.

Influence of Essential Oil Components on Growth Performance and the Functional Activity of the Pancreas and Small Intestine in Broiler Chickens

To investigate the efficacy of alternatives to antibiotics, the present study was conducted to compare the effects of antibiotic, lactic acid, a blend of commercial essential oils (EOs) and EOs in combination with lactic acid on growth performance and the functional activity of the gut in broiler chickens. A total of 168 broiler chickens were given the basal diet supplemented with 10 ppm colistin (T1), 0.1% lactic acid (T2), 25 ppm EOs (T3), 25 ppm EOs+0.1% lactic acid (T4), 50 ppm EOs (T5) or 50 ppm EOs+0.1% lactic acid (T6) in the period 3 to 35 days of age. As a result, the broiler chickens assigned to T4 group throughout the experimental period had apparently (p<0.05) greater body weight and total gain than these assigned to T1, T2, T3 and T5 groups. However, there was no difference in growth performance among the birds fed the diets supplemented with antibiotic (T1), lactic acid (T2) and EOs (T3 and T5) alone. The weights of digestive organs and the number of lactobacilli and E. coli in the lower ileum were not affected by dietary treatments. Total trypsin activity was significantly (p<0.05) greater in T4 than T1, T2, T3 and T5 groups. Total and specific pancreatic α- amylase activities were significantly (p<0.05) enhanced in the broiler chickens fed T4 diet compared with these fed T1, T2 and T3 diets. However, there were no differences in growth performance and digestive enzyme activities including pancreatic trypsin and α-amylase between T4 and T6 groups fed the diets supplemented with either low or high EOs levels in combination of lactic acid. In conclusion, a blend of commercial EOs combined with lactic acid showed significant increases in digestive enzyme activities of the pancreas and intestinal mucosa, leading to increase in growth performance. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 3 : 394-400)

Efeitos da moagem dos ingredientes e da forma física da ração sobre o desempenho de frangos de corte

Dois experimentos foram conduzidos com o objetivo de comparar os efeitos das moagens conjunta e separada dos ingredientes e das formas físicas da ração sobre o desempenho dos frangos de corte e sobre o peso dos órgãos digestivos. No primeiro experimento foram utilizadas 1200 aves da linhagem Avian Farms, de 1 a 43 dias de idade e no segundo, 256 aves da mesma linhagem, de 1 a 41 dias de idade. Os tratamentos consistiram de dois sistemas de moagem (conjunta e separada) e duas formas físicas (granulada e farelada) das rações. Aos 43 dias de idade os frangos que consumiram as dietas granuladas com moagem separada e conjunta e fareladas com moagem separada e conjunta pesaram 2,54, 2,48, 2,37 e 2,27kg/ave, respectivamente. O consumo de alimento teve a seguinte ordem decrescente: 4,73, 4,88, 4,54 e 4,35kg/ave para as rações granuladas com moagem separada e conjunta e rações fareladas com moagem separada e conjunta, respectivamente (P&lt;0,05). A melhor conversão alimentar foi obtida com a ração granulada submetida à moagem separada e a mortalidade mais elevada foi observada nas aves que receberam a dieta granulada com moagem conjunta. Os pesos da moela e do pâncreas (% peso corporal) foram menores (P&lt;0,05) com a ração granulada e moagem conjunta .

Effect of soaking, germination, and enzyme treatment of whole barley on nutritional value and digestive tract parameters of broiler chickens

1. An experiment was carried out to determine the effect of soaking at 0°C, soaking at room temperature, germination, or enzyme treatment of whole barley on feeding value and digestive tract parameters of 2‐ to 4‐week old broiler chickens given diets with 700g/kg whole barley. 2. Soaking or germination decreased the soluble and total β‐glucan content (P<0.05) and, except for soaking at 0°C, the acid extract viscosity of the grain also decreased (P< 0.05). Germination and soaking in the presence of enzymes produced the lowest β‐glucan content and viscosity. 3. Except for soaking in cold water, the soaking, germination and enzyme treatments increased weight gain and decreased food: gain ratio (P< 0.05). Correspondingly, the digestibility of protein, fat, and ash, and the digestible energy content, increased (P< 0.05) after enzyme treatment or germination. 4. Chickens fed on enzyme‐treated or germinated barley diets had intestinal contents with a greater proportion of dry matter and lower viscosity than chickens fed on untreated barley (P< 0.05). Consequently, the cages and chickens were cleaner (P< 0.05) and the weight of digestive organs as proportion of live weight was lower. 5. Particle size analysis of excreta revealed that whole barley was efficiently ground by the gizzards of 16‐d‐old chickens, and very few whole kernels were found.

Response of Broiler Chicks Fed a High-Tannin Sorghum Diet

This study was conducted to evaluate the overall performance and possible changes in digestive organ weights in male broiler chicks fed a tannin-containing sorghum (HTS) diet. The effects of switching diets from corn-based to sorghum-based and vice versa were also investigated. Diets were formulated to be both isoenergetic and isonitrogenous and fed to 21 days in a completely randomized design.HTS birds consumed more feed and gained more weight during 0-9 days than their corn-fed counterparts, although overall performance in terms of weight gain and feed efficiency was similar. Metabolizable energy and efficiency of nitrogen utilization of the HTS diet was poorer than that of the corn control. Feeding HTS followed by a corn-based diet did not result in better performance by 21 days of age. Apart from liver weights on day 9, organ weights were similar for all treatments and did not show any evidence of adaptation to the diet.

Dietary Fiber Viscosity and Amino Acid Digestibility, Proteolytic Digestive Enzyme Activity and Digestive Organ Weights in Growing Rats

The effect of dietary fiber viscosity on apparent ileal nitrogen and amino acid digestibility, proteolytic enzyme activity and digestive organ weights was investigated. Eighteen growing rats were fed for 21 d purified casein-based diets containing carboxymethylcellulose (50 g/kg) of low (20 cP), medium (800 cP) and high (2000 cP) viscosity (LV, MV and HV treatment groups, respectively). Dietary fiber viscosity did not significantly affect apparent ileal (terminal 15 cm of the ileum) nitrogen or amino acid digestibility, trypsin or chymotrypsin activity in the small intestinal contents and pancreatic tissue, aminopeptidase-N activity in the small intestinal contents and tissue, or the weights of the stomach, pancreas, small or large intestines. Intragastric pepsin activity in LV rats was significantly higher than in MV or HV rats (P < 0.01), but fiber viscosity did not affect pepsin activity in the stomach tissue. The intragastric pH of the HV and MV rats was significantly higher than that for the LV rats (P < 0.01). The stomach contents (dry matter) of MV and HV rats were greater than in LV rats (P < 0.05). Delayed passage rate of the more viscous digesta may have resulted in greater absorption of amino acids, because the HV rats had a higher estimated true ileal digestibility than the LV animals for threonine, serine, aspartic acid, glutamic acid, histidine, tyrosine and phenylalanine.

Effect of Early Feed Restriction and Realimentation on Heat Production and Changes in Sizes of Digestive Organs of Male Broilers

Two experiments were conducted with broilers to determine the effect of early feed restriction and realimentation on metabolic heat production and changes in sizes of digestive organs. An indirect open circuit calorimeter was used. Treatments were a full-fed control (FF) and a feed-restricted group (FR). Feed during the restriction period (6 to 12 d) for the FR birds was limited to 50% of voluntary feed intake of the FF birds. This was followed by realimentation period when all birds were provided feed for ad libitum consumption. The purpose of Experiment 1 was to measure basal metabolic rate (BMR), and Experiment 2 was designed to measure 36-h fasting metabolic rate (FMR), in both cases during time of restriction and realimentation. At the end of the 36-h unfed period, birds were killed and their digestive organs excised, blotted, and weighed.The FR birds showed significantly (P < .01) lower BMR compared with the FF birds during the restriction period. This lower BMR did not carry over into the refeeding period, when there was no difference between the two treatments. Thirty-six-hour FMR, like the BMR was also lower for FR compared with FF birds, but only during the period of restriction. Weights of digestive organs (expressed as a percentage of BW) during restriction were generally heavier for FR compared with FF birds. Measurements of organ weights taken during realimentation show significantly (P < .05) heavier liver and pancreas for FR compared with FF birds. Results of these experiments suggest that lower MR of “restricted-refed” birds does not play a role in the ability of the birds to show improved feed efficiency and growth compensation. Greater feed intake relative to BW and its associated digestive adaptations seem to be contributing factors to any growth compensation.

Effects of oral IGF-I or IGF-II on digestive organ growth in newborn piglets.

To study whether colostrum-borne growth factors are responsible for the rapid GI tissue growth in naturally suckled newborn animals, newborn unsuckled piglets were bottle-fed for 24 h with infant milk formula with or without addition of 2 micrograms/ml of recombinant human insulin-like growth factor-I (IGF-I) or insulin-like growth factor-II (IGF-II), a level which approximated that of porcine colostrum. The animals were then sacrificed for measurements of their digestive organ weights and contents of protein, RNA and DNA in the organs. The treatment with IGF-I or IGF-II failed to show any significant effect on the weight of the esophagus, stomach, small intestine, large intestine, mandibular glands, kidneys and the spleen, and had no effects on the contents of protein, RNA and DNA in the small intestinal mucosa, the liver and the spleen. However, piglets fed with infant formula containing IGF-I (n = 7) or IGF-II (n = 7) had a heavier pancreas (p < 0.05) compared to formula-fed controls (n = 7). The DNA content in the stomach and the pancreas were greater in animals treated with IGF-I or IGF-II than in controls. Using a cell labelling technique it was shown that both IGF-I and IGF-II stimulated cell proliferation in the small intestinal crypts. The results indicate that the substantial GI tissue growth reported in newborn animals is unlikely due to colostrum-borne IGF-I or IGF-II alone. On the other hand the study does suggest that oral IGF-I and IGF-II are capable of stimulating cell proliferation in the GI tract.

Comparative growth and development of the digestive organs and of some enzymes in broiler and egg type chicks after hatching

1. Body weight, the weight of digestive organs and activities of some digestive enzymes were determined from hatching to 14 d of age in meat- and egg-type chickens. 2. Relative daily food intake and growth rate were much higher in meat- than in egg-type chickens. Relative daily food intake peaked at 30% of body weight at 3 d of age in meat-type, and at 20% of body weight at 6 d of age in egg-type chickens and then decreased gradually. The corresponding values for growth rate were 20 and 14%. 3. Allometric growth of the small intestine, intestinal contents and liver was greater in meat-type chickens, but the growth of the pancreas attained a higher value in the egg-type birds. Diminution of the vitelline residue was similar in the two breeds. 4. Pancreatic digestive enzyme activities were similar between stocks, but activities in the small intestinal contents were lower in meat-type chickens. 5. The secretion of digestive enzymes in the newly-hatched meat-type chicken could be a limiting factor in digestion and, consequently, in food intake and growth.

Relationships of Weight Gain and Behavior to Digestive Organ Weight and Enzyme Activities in Piglets1

Organ weights and digestive enzyme contents of the pancreas, stomach and duodenum were measured in 75 nursing piglets at 21 d of age. Piglets were given creep feed from 10 d of age. Creep feed intake was less than 1.5 g.d-1.piglet-1 up to d 18; on d 19 and 20 it averaged 15 g.d-1.piglet-1. On d 10, piglets went to the feeder more frequently than on the following days. Feeding bouts were longer on d 16, 17 and 18 just prior to the increase in creep feed consumption. Means and SE for the parameters studied at 21 d of age were 7.01 +/- .18 mg for pancreas weight; 61,499 +/- 4,091 units of amylase (UA) and 1,510 +/- 110 UA/mg DNA; 2,962 +/- 189 units of chymotrypsin (UC) and 68.94 +/- 3.92 UC/mg DNA; 8.76 +/- .35 g for fundic mucosa weight; 558,875 +/- 49,287 units of pepsin (UP) and 12,338 +/- 1,175 UP/mg DNA; 1.75 +/- .06 g for duodenum weight; 1.39 +/- .07 units of maltase (UM) and .14 +/- .006 UM/mg DNA. Day-0 weight was not correlated with 21-d gain. Feeding behaviors were correlated positively with 21-d gains. Feeding behaviors and behaviors were correlated positively to pancreas total and specific enzyme contents as well as to stomach and duodenum weights, RNA/DNA ratios of the pancreas and the stomach and protein/DNA of the pancreas but were correlated negatively with specific and total pepsin and maltase activities. Variation was large in enzyme activities (cv = 35 to 82%).(ABSTRACT TRUNCATED AT 250 WORDS)

Winter diet and intestinal proportions of rock and willow ptarmigan and sharp-tailed grouse in Ontario

Dwarf birch (Betula glandulosa) and willow (Salix spp.) were the principal winter foods of sympatric willow ptarmigan (Lagopus lagopus), rock ptarmigan (Lagopus mutus), and sharp-tailed grouse (Tympanuchus phasianellus) in northern Ontario. Birch catkins and leaf buds made up 90 and 69% of the diet of sharp-tailed grouse and rock ptarmigan, respectively, whereas willow stems and buds formed 68% of the willow ptarmigan diet. Digestive organ weights differed significantly (P &lt; 0.05) among the species of grouse during winter. Within each species, weights of gizzard, caeca, and small intestine were weakly correlated with individual body weight. Total variance in the weight of each digestive organ among species was partitioned into significant effects of species body weight and also species. Seasonal changes to lighter caeca and small intestines were apparent in prebreeding willow ptarmigan and rock ptarmigan coincident with a change in diet to green, growing willow and birch parts. A precise effect of type of diet upon the digestive organ weight of different grouse species was not perceived and was confounded by influences of species body weight.

Body Weight and Composition Changes and Adaptations for Breeding in Wood Ducks

The weight and carcass composition of Wood Ducks (Aix sponsa) collected in southeast Missouri were analyzed during fall and at specific stages of the reproductive cycle. Males lost 4% of their body weight between fall and spring. Decreases in the weights of digestive organs were primarily responsible for the change. The body weights of hens increased 14% between fall courtship (618 g) and the maximum attained during laying (706 g). Nearly all of the weight gain of females occurred on the breeding grounds and was the result of fat deposition and increases in the weights of the reproductive organs. Body weights of hens decreased 164 g during laying and incubation. Utilization of stored fat for egg production accounted for most of this weight loss. The lack of significant changes in the ash-free lean dry mass of the carcass as well as a change in food habits indicated that the protein requirements for the clutch are obtained by foraging for invertebrates during laying. Weight losses during incubation were small, indicating that hens are able to meet nearly all incubation energy requirements by foraging during inattentive periods. Female Wood Ducks satisfy their nutrient and energy requirements during the reproductive cycle by foraging and the use of endogenous reserves. Adaptations that maximize the use of stored lipids for egg production and facilitate the conservation of endogenous protein and the acquisition of dietary protein enable hens to produce and incubate large clutches of relatively large eggs without significant changes in body protein. Studies of weight changes in breeding ducks (Weller 1957, Folk et al. 1966, Harris 1970, Korschgen 1977, Landers et al. 1977) have shown that the body weights of females increase prior to clutch initiation and then decline rapidly during laying and incubation. These weight changes have been attributed primarily to the growth and subsequent involution of the ovary and oviduct and fat deposition and mobilization. Changes in the weights of digestive organs and atrophy or mobilization of muscle tissue have also been implicated, but to a lesser degree. Although previous investigators have identified the variables that influence changes in body weight, these variables (especially changes in carcass composition) have not been well measured at specific stages throughout the reproductive cycle for ducks. Information of this kind is nevertheless needed to meaningfully interpret weight data collected in the field and to better understand adaptations for breeding and the impact of reproductive efforts on the physiological condition of hens. The results reported here represent a portion of the data collected during a three-year study of the feeding ecology, nutrition, and reproductive bioenergetics of Wood Ducks (Aix sponsa; Drobney 1977). The purpose of this paper is to quantify the variables responsible for changes in body weight during the reproductive cycle and to relate changes in carcass composition to the breeding biology of Wood Ducks. STUDY AREA AND METHODS Body and organ weights were obtained from 159 Wood Ducks (84 females and 75 males) co lec ed during 1975-1977 on the Duck Creek Wildlife Management Area in southeastern Missouri. All birds except for six hens that were removed from nest boxes, were obtained by shooting in flooded timber foraging areas during morning (06:00-11:00) and afternoon (15:00-19:00) collection periods. Carcass analyses were performed only on the 1976-1977 sample consisting of 43 females and 38 males. Following collection, birds were taken to the laboratory, weighed, and dissected. Fat attached to mesenteries and internal organs was removed and weighed, but not included in the carcass composition analyses. These fat deposits are referred to as visceral fat in this paper. Internal organs (contents removed) were weighed to the nearest 0.01 g (wet weight). Birds that were to be analyzed for carcass composition were plucked, sealed in plastic bags, and frozen. Carcass composition was analyzed using methods described by Rogers and Odum (1964), Ricklefs (1967), and Brisbin (1968). Before processing, birds were removed from the freezer and thawed for approximately 30

Gut Morphology of Mallards in Relation to Diet Quality

Digestive organ lengths, weights, and volumes in each of three groups of mallards (Anas platyrhynchos) were determined at the end of a 21-day period, during which one group was fed turkey starter (control diet), another group was fed whole corn (low fiber content), and the third group was fed alfalfa pellets (high fiber content) to demonstrate the adaptive efficiency of the waterfowl gut to diets of varying quality. Food consumption by the alfalfa-fed ducks was significantly greater (P ( 0.01) than the other two groups. All digestive organs of the alfalfa-fed ducks were significantly larger (P < 0.01) than those of the cornand turkey starter-fed ducks at the end of the study. It is concluded that mallards can adapt rapidly to fibrous, relatively indigestible foods. This ability may have survival value when higher quality foods are unavailable or when food habits change rapidly during migrations. J. WILDL. MANAGE. 39(1):168-173 The ability of wild birds to survive on low quality foods (herein defined as foods relatively indigestible because of high fiber content), and the changes that occur in gut morphology and function in order to do so, have received relatively little attention. In gallinaceous birds, consumption of high quality diets (low fiber content, easily digested) is correlated with short guts and ceca, while consumption of low quality diets results in longer guts and ceca (Leopold 1953, Lewin 1963, Gardarsson 1971, Moss 1972, Pendergast and Boag 1973). These relationships need investigation in waterfowl. An increase in the efficiency of utilization of low quality foods may have survival value when favored, highly nutritious foods are not available. The purpose of this paper is to demonstrate the short term adaptive response of mallards to foods of varying quality by measuring differences in gut morphology among groups of these ducks fed different diets. I wish to thank D. G. Raveling for arranging financial support, for encouragement during the study, and for editorial assistance and guidance on the manuscript. R. G. Schwab provided the ducks, and R. Cole and K. Miller assisted me during the

Effect of “Meal Eating” Versus “Nibbling” on Body Composition and Digestive Organ Weight of Normal and Cropectomized Chickens

The crop was surgically removed from one week old chickens. The effects of meal eating (two one-hour feeding periods per day) versus nibbling (food available continuously) was then studied in cropectomized and normal birds. In one experiment, birds remained on their particular feeding schedule until they attained a given body weight. In a second experiment, food intake was equalized among all four groups with two groups consuming it in two one-hour periods, the other two throughout the day. Meal eating significantly increased the weight of the esophagus and gizzard plus the proventriculus. Body fat was significantly reduced and body water increased on meal eating. Protein content of carcass remained unaltered. Crop removal in the chicken greatly exaggerated the effects of meal eating. The effects of meal eating versus nibbling on body composition are the reverse of those observed in the rat.